Basic Seed implementation added #36

include/nil/crypto3/block/detail/seed/seed_functions.hpp

@@ -0,0 +1,40 @@
+//---------------------------------------------------------------------------//
+// Copyright (c) 2018-2020 Mikhail Komarov <nemo@nil.foundation>
+//
+// Distributed under the Boost Software License, Version 1.0
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+//---------------------------------------------------------------------------//
+
+#ifndef CRYPTO3_SEED_FUNCTIONS_CPP_HPP
+#define CRYPTO3_SEED_FUNCTIONS_CPP_HPP
+
+#include <boost/endian/arithmetic.hpp>
+
+#include <nil/crypto3/detail/basic_functions.hpp>
+
+namespace nil {
+    namespace crypto3 {
+        namespace block {
+            namespace detail {
+                template<std::size_t WordBits>
+                struct seed_functions : public ::nil::crypto3::detail::basic_functions<WordBits> {
+                    typedef typename ::nil::crypto3::detail::basic_functions<WordBits>::word_type word_type;
+
+                    constexpr static const std::size_t constants_size = 256;
+                    typedef std::array<word_type, constants_size> constants_type;
+
+                    inline static word_type g(word_type X, const constants_type &s0, const constants_type &s1,
+                                              const constants_type &s2, const constants_type &s3) {
+                        return (s0[::nil::crypto3::detail::extract_uint_t<CHAR_BIT>(X, 3)] ^
+                                s1[::nil::crypto3::detail::extract_uint_t<CHAR_BIT>(X, 2)] ^
+                                s2[::nil::crypto3::detail::extract_uint_t<CHAR_BIT>(X, 1)] ^
+                                s3[::nil::crypto3::detail::extract_uint_t<CHAR_BIT>(X, 0)]);
+                    }
+                };
+            }    // namespace detail
+        }        // namespace block
+    }            // namespace crypto3
+}    // namespace nil
+
+#endif    // CRYPTO3_SEED_FUNCTIONS_CPP_HPP